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Ch.1 - Introduction: Matter, Energy, and Measurement
Chapter 1, Problem 26

A baseball weighs 145.4 g. What is the kinetic energy, in joules, of this baseball when it is thrown by a major league pitcher at 150 km/h?

Verified step by step guidance
1
Convert the mass of the baseball from grams to kilograms by dividing by 1000, since the standard unit of mass in physics is kilograms.
Convert the speed of the baseball from kilometers per hour to meters per second. Use the conversion factor: 1 km/h = 0.27778 m/s.
Use the formula for kinetic energy: \( KE = \frac{1}{2}mv^2 \), where \( m \) is the mass in kilograms and \( v \) is the velocity in meters per second.
Substitute the converted mass and velocity values into the kinetic energy formula.
Calculate the expression to find the kinetic energy in joules.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Kinetic Energy

Kinetic energy is the energy an object possesses due to its motion, calculated using the formula KE = 0.5 * m * v², where m is the mass in kilograms and v is the velocity in meters per second. This concept is crucial for determining how much energy the baseball has when thrown.
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Kinetic & Potential Energy

Unit Conversion

Unit conversion is the process of converting a quantity from one unit to another, which is essential in this problem since the baseball's mass is given in grams and the velocity in kilometers per hour. Understanding how to convert grams to kilograms and kilometers per hour to meters per second is necessary to apply the kinetic energy formula correctly.
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Conversion Factors

Mass and Velocity Relationship

The relationship between mass and velocity is fundamental in physics, particularly in the context of kinetic energy. A heavier object or a faster-moving object will have greater kinetic energy, which highlights the importance of both mass and speed in calculating the energy of the baseball when thrown.
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Velocity Distributions